Radio port controller in a wireless personal communication system

ABSTRACT

A preferred embodiment provides a radio port controller in a wireless personal communications system including a first interface module in communication with a radio port, a second interface in communication with a digital switch, and at least one switching transcoder module in communication with the first and second interface modules. A further preferred embodiment provides that the switching transcoder module includes a digital signal processor. The radio port controller preferably has a communication backplane including a plurality of slots, and each slot is preferably adapted to selectively receive either a T1 card interfacing to a T1 line or an E1 card interfacing to an E1 line.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation in part of application Ser.No. 08/344,272, (pending) filed Nov. 23, 1994, entitled "WirelessPersonal Communication System," by inventors K. Ganesan, et. al. Theabove identified application in its entirety is incorporated herein byreference.

BACKGROUND OF THE INVENTION

Wireless access communications systems (WACS) strive to provide flexiblewireless communication services. WACS, may provide a system forimproving or eliminating drop wire requirements to homes and businesses.Although cellular telephones and cordless telephones also providewireless features, certain limitations are inherent in each of thesesystems. Cellular telephones typically transmit signals to cellular basestations at relatively high power levels. The high power levels requireFederal Communications Commission (FCC) approval and careful frequencyplanning to avoid unwanted interference. Additionally, the cellular basestations tend to be complicated and expensive units. Cordless telephonesare lower power devices, but the transmission frequencies are usuallyprone to interference. Also, cordless phones require wire connections tothe public telephone lines and cannot communicate with wireless accesscommunication Personal Communication Services (PCS) systems.Furthermore, cellular phones and cordless phones are generally notcapable of supporting both voice and data transmissions.

A typical architecture for a wireless PCS system includes subscriberunits (SUs), radio ports (RPs), one or more radio port controllers(RPCs), sometimes referred to as radio port control units (RPCUs) inother publications, and an access manager (AM). The SUs transmitinformation to the RPs using radio frequencies. RPs are usually smalldevices that are typically mounted to a utility pole. The RPs areconnected to an RPC using wireline facilities. Each RPC is connected toa switch that is part of the public switched telephone network (PSTN)and the AM. The AM provides overall coordination of the call handoffacross RPCs, has the function of mobility management, and supportssubscriber related features such as registration and authentication.

A consortium of telecommunication entities has recently developed aproposed standard for providing WACS PCS. This standard outlines theabove-mentioned architecture. Further details concerning this proposedstandard are set out in Bellcore Corp. publication TR-INS-001313entitled Generic Criteria for Version 0.1 Wireless Access CommunicationsSystems (WACS) published October 1993 (hereinafter "Generic Criteria").The publication is available to those interested in WACS PCS fromBellcore Corp. at Bellcore, Customer Services, 8 Corporate Place - Room3C-183, Piscataway, N.J. 08854-4156, or at 1 (800) 521-CORP. Also, thereader may refer to Bellcore manual SR-ARH-002315 that describesspecific modulator and demodulator requirements in the SU and the RP.Additionally, the U.S. Telecommunications Industry Association (TIA) hasrecently approved a PACS standard as set forth in TIA publicationJTC(AIR)/95.4.20-033R2. The reader is presumed to be familiar with thesespecifications and with related technological issues known to thosehaving ordinary skill in the art.

Although general standards have been set forth, advances andimprovements to the technology have been discovered includingimplementation of novel configurations and circuitry. The preferredembodiment is primarily directed toward improvements relating to theRPC.

SUMMARY OF THE INVENTION

The preferred embodiment of the present invention relates to a radioport controller in a wireless personal communications system including afirst interface module in communication with a radio port, a secondinterface module in communication with a digital switch, and at leastone switching transcoder module (STM) in communication with the firstand second interface modules. The STM preferably includes at least onedigital signal processor (DSP) having an interrupt of less than 1millisecond. The first interface module preferably includes a T1 cardthat is coupled to a T1 communication line. The second interface modulepreferably includes an E1 card coupled to the digital switch.

The RPC preferably has a communication backplane including a pluralityof slots. Each slot is preferably adapted to selectively receive eithera T1 card interfacing to a T1 line or an E1 card interfacing to an E1line.

Each STM is preferably connected to a separate T1 line. Each STMpreferably has at least one DSP capable of processing both digitizedvoice and personal communication system messages. In one preferredembodiment, the STM includes at least one DSP handling both incoming andoutgoing message traffic. The DSP may handle from two to four differentconversations at the same time.

In another preferred embodiment, the STM has a first digital signalprocessor assigned to process incoming voice and data messages and asecond digital signal processor assigned to process outgoing voice anddata messages. The STM may further include a plurality of memory buffersin communication with the DSPs. The buffers may be circular buffersadapted to receive and transmit personal communication system messagesfrom an RP or from a digital switch. Each STM may further include acentral processor for allocating each time slot in each T1 communicationline to at least one of the DSPs. The central processor preferablycommunicates with each DSP using inter-processor data messages.

The RPC preferably includes a call control processor including statemachines for processing ISDN layers one, two, and three and WACS layerthree protocols. In one embodiment, the RPC includes at least one globalresource processor for balancing loading among various other callcontrol processors in the RPC. The RPC may further include a disk drivecoupled to the global resource processor. The global resource processormay cooperate with the disk drive to perform at least some accessmanager functions.

The RPC also preferably includes a channel access processor (CAP) forprocessing layer 2 personal communication system messages. Each of theprocessors within the RPC may execute a multi-tasking operating system.The multi-tasking operating system allows processors to create a threadthat is associated with a routine executed by the processor. In oneembodiment, a thread is created by the operating system for at least oneroutine performing call processing functions.

The invention itself, together with further attendant advantages, willbest be understood by reference to the following detailed description,taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless access communication system.

FIG. 2 is a block diagram showing functions to be performed by an RPC.

FIG. 3 is a block diagram illustrating one preferred embodiment of anRPC.

FIG. 4 is a block diagram of one preferred embodiment of an STM that maybe used within the RPC of FIG. 3.

FIG. 5 is a functional block diagram of a central processor that may beused in an STM within an RPC.

FIGS. 6-11 are diagrams various internal of communication messages whichmay be used within the STM of FIG. 4.

FIG. 12 is a preferred DSP assignment table in the central processor ofFIG. 5.

FIG. 13 is a functional block diagram of a CAP which may be used withinan RPC.

FIG. 14 is a functional block diagram of a CCP that may be used withinan RPC.

FIG. 15 is a functional block diagram of a global resource processor(GRP) that may be used within an RPC.

FIGS. 16-19 are message flow diagrams showing a preferred embodiment ofvarious messages between an RPC and an SU.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a general block diagram of a wireless accesscommunication system (WACS) 10. The WACS 10 includes subscriber units(SU) 20, radio ports (RP) 50, radio port control units (RPC) 60, anoperations maintenance center (OMC) 70, a local digital switch (LDS) 80,and an access manager (AM) 90. The SU 20 communicates with the radioport 50 via an air interface. Each RP 50 communicates with an RPC 60 viatransmission lines, typically standard T1/DS1 lines. The RPC 60 controlsradio links via the RP 50, while transmission lines carry various voiceand data communications. The switch 80 controls access between wirelessaccess communication systems (WACS) 10 and the public switch telephonenetwork (PSTN) 12. The AM 90 provides call control and also communicateswith the switch 80 providing voice paths between the WACS network andthe PSTN. Additional details are known to those skilled in the art andare set forth in the Bellcore "Generic Criteria". Recently, a newerproposed standard, personal access communications (PACS), has beenintroduced. Both WACS and PACS standards, however, may be implemented onthe system described below.

A central component in the wireless personal communication system is animproved radio port controller (RPC) 300 as shown in FIG. 2 of thepreferred embodiment. The RPC 300 manages RP 50 resources and controlsthe transport of information between a network switch 80 and itsassociated RPs 50.

The RPC 300 interfaces with at least one RP 50 and with at least oneswitch 80. The RP 50 interface is preferably a DS1 layer 1 unchannelizedinterface allowing a 1.544 Mb/s clear channel and a TDM/TDMA layer 2interface mapping the TDM/TDMA time slots to the DS1 channel. The RPC300 to switch 80 interface is preferably a DS1 physical interface usingthe multiplexed ISDN Basic Rate Interface BRI communication protocoldefined in the Bellcore specification.

In the basic configuration contemplated by the Bellcore specification,the RPC 300 performs call processing functions and transcodes compresseddata into full PCM data and vice-versa. The RPC 300 exchanges signalinginformation with the SU 20 and collects performance monitoringinformation (e.g. radio link quality, channel usage, channel allocation,traffic data, and system capacity information).

The RPC 300 further includes an RP DS1 line interface 301 connected toRPs 50 over RP DS1 communication links 318 and a switch DS1 lineinterface 302 connected to the switch 80 over switch DS1 communicationlinks 320. The RPC 300 also includes a first interface module performingradio interface functions 308 in communication with the RP DS1 lineinterface 301 through an RP-T1 bus 306 and a second interface moduleperforming switch interface functions 310 in communication with theswitch DS1 line interface 302 through a switch T1 bus 304. The radiointerface 308 and the switch interface 310 are connected to an auxiliarycommunication function 312. The auxiliary communication functions 312preferably interface with the AM 90 over a first Ethernet TCP/IPinterface 314 and is connected to the OMC 70, preferably over a secondEthernet TCP/IP interface 316.

The RP-DS1 line interface functions 301 preferably consist of thephysical, mechanical, and electrical functions required to support the1.544 Mb/s DS1 lines 318 to the RPs 50. The switch-DS1 line interfacefunctions 302 preferably consist of the physical, mechanical, andelectrical functions required to support the 1.544 Mb/s DS1 lines 320 tothe switch 80.

The radio interface functions 308 include multiplexing anddemultiplexing wireless personal communication system (WACS or PACS)traffic and signaling information into the unchannelized DS1 interfaceto the RP 318. The radio interface 308 also inserts unused bits in theRP DS1 interface 318 due to timing differences between the 1.544 Mb/sDS1 line and the RP 50 time slots. In addition, the radio interfacefunctions 308 generate a TDM/TDMA synchronization pattern for the RP DS1interface 318. The radio interface 308 also transcodes compresseddigitized speech into mu-law PCM speech and transcodes mu-law PCM speechinto compressed digitized speech. Currently, the RPC 300 compressesspeech using 32 kb/s ADPCM encoding; however, other compression schemesmay be used such as but not limited to 16 kb/s LDCELP or ADPCM typecompression. Also, although mu-law PCM is used for uncompressed speech,other digital representations of speech may be used such as A-law PCM.

The radio interface functions 308 include error checking of wirelesspersonal communication system layer 2 information preferably using a16-bit checksum, and processing radio link quality measurements such asword error indication bits and co-channel interference codes receivedfrom the RP 50 over the RP DS1 interface 318. The radio interface 308also processes layer 2 wireless personal communication system signalingmessages. In addition, the radio interface 308 maintains TDM/TDMAtimeslot status information such as busy/idle and per-call informationfor each active call. Finally, the radio interface 308 multiplexesalerting channel and system information channel information based onpriority onto a system broadcast channel that is sent over the RP DS1communication link 318.

The switch interface functions 310 include signaling functions requiredto interface to the switch. More specifically, the switch interface 310receives and transmits call processing messages to the switch. In apreferred embodiment the communication protocol to the switch over theDS1 interface 320 consists of up to eight ISDN basic rate interfaces(BRI) and the switch interface 310 receives, transmits, and processesISDN communication messages. However, the interface 320 may be any otherdigital communication method such as ISDN primary rate interface (PRI)or an optical interface such as SONET. The switch interface functions310 also interface with the auxiliary communication functions 312 suchas incoming call processing and OMC functions. The switch interfacefunctions 310 communicate with the radio interface functions 308 usingthe switch T1 bus 304 when processing outgoing calls.

The auxiliary communication functions 312 coordinate activities ofvarious RPs 50 such as by maintaining per-RP information including e.g."up/down" status, radio link quality, channel usage data, and trafficstatistics. The auxiliary communication functions 312 route calls fromthe switch 80 to the proper RP 50. The auxiliary functions 312 alsoinclude sending, receiving, and processing layer 3 wireless personalcommunication messages to and from the AM 90 using the first EthernetTCP/IP interface 314. The auxiliary functions 312 interface to the OMC70 over the second Ethernet interface 316 to monitor and control asoftware downline load function such as when a new version of softwaremay be downloaded to a component of the system. Such downloading isparticularly useful for updating software in the SU 20.

FIG. 3 shows a component block diagram of a preferred embodiment of anRPC 330. The RPC 330 includes a global resource processor (GRP) 332, aswitching transcoder module (STM) 334, a common access processor (CAP)336, and a call control processor (CCP) 338.

The GRP 332 communicates over a backbone LAN 352 to the OMC 70 and tothe AM 90. The GRP 332 also communicates with at least one CAP 336 andat least one CCP 338 over an internal LAN 350. The GRP 332 providesaccess to the external backbone LAN 352 and performs network managementand other centralized RPC 330 functions. Each CAP 336 preferablycommunicates with up to eight STMs 334 over a high speed VME bus 348.Each STM 334 is connected to both the T1 bus 344 and the E1 bus 346.Also, each CCP 338 is connected to the E1 bus 346.

As shown in FIG. 3, the RPC 330 preferably includes up to five CAPs 336,and four CCPs 338. Although FIG. 3 shows a specific number of eachcomponent, the preferred embodiment may include additional components.Specifically, the preferred embodiment may support additional componentssuch as extra GRPs 332, CCPs 338, CAPs 336 and STMs 334.

The RPC 330 also includes a T1 bus 344 and an E1 bus 346. The T1 bus 344interfaces to a plurality of RP T1 cards 342. Each T1 card 342 cansupport up to two T1 lines 356, each interfacing with an RP 50. The T1card 342 communicates with the T1 bus 344 over a T1 bus slot connector354. Similarly, a T1 switch card 340 may communicate with the switchover two T1 lines 360. The T1 switch card 340 is coupled to an E1 busslot connector 358 connected to the E1 bus 346. The RP T1 card 342 maybe installed in slots 1, 3, 5, 7 of a backplane (not shown) providing upto 8 T1 lines to the RPs 50. The switch side T1 cards 340 may beinstalled preferably in slots 9, 10, 11, 12, 13 of the backplaneproviding up to 10 T1 lines 360 to the switch.

In addition, as more processors are added, additional T1 cards 342 andT1 switch cards 340 may also be added. Also, it should be noted that theE1 bus 346 may also support E1 cards as well as T1 cards 349 for use incountries other than the United States such as in Europe. In a preferredembodiment, the backplane associated with the E1 bus 346 has a pluralityof slots and each slot is associated with a connector adapted to receivean interface card 340 such as either a T1 or an E1 card. The T1 cards340 preferably include a first set of pin outs for carrying a T1 signalfor use with a T1 bus and a second set of pin outs for carrying an E1signal for use with the E1 bus. The connector, preferably a singleuniversal connector, electrically connects the E1 bus 346 to theinterface card 340 (T1 or E1). Preferably, the E1 bus derives a 2 Mb/sclock signal from at least one of the T1 cards by speeding up the 1.544Mb/s clock corresponding to the T1 line connected to the switch. The E1bus therefore may carry up to 32 DS0 time slots although only 24 ofthese time slots are used by a T1 card.

In one embodiment, the type of card, T1 or E1, supported by each slotmay be configured in software. Other techniques for sensing the natureof an inserted card (T1 or E1) and appropriately configuring the busconnections may similarly be used.

Each STM 334 receives and transmits wireless personal communicationsystem interface frames to and from an RP 50 via one T1 line 356 and theT1 backplane bus 344. Preferably, one STM 334 is used to handle eitherone or two T1 lines 356 to the RP 50. Each STM 334 also receives andtransmits speech data to and from the switch on DS0 slots on any of theT1 lines 360 connected to the E1 backplane bus 346.

The CAP 336 provides interrupt timing to the STMs 334 and sends commandsto the STMs 334 over the VME bus 348. The VME bus 348 allows the CAP 336to directly access, read or write the local memory within each STM 334.The CAP 336 can also access the backplane T1 bus 344. The CAP 336communicates with the CCP 338 and the GRP 352 over the internal LAN 350.

The CAP 336 includes a common processor module (CPM) containing aprocessor such as an INTEL 960 processor including associated circuitryand a communication chip interface such as the AT&T SPYDER chip. Thecommon processor communicates with either the T1 bus 344, the E1 bus346, the LAN 359, or the VME bus 348.

Each CAP 336 manages and supports maintenance of radio links for up to 8STMs 334. Each CAP 336 maintains information such as STM numbers, radioport IDs, RF carriers and TDM/TDMA time slots used by the radio link aswell as the radio link status. Each CAP 336 generates STM 334synchronization interrupts and forwards wireless personal communicationsystem layer 3 messages received from the STM 334 to the CCP 338 andsends messages from the CCP 338 to the STM 334. The CAP 336 alsoprocesses wireless personal communication system layer 2 messages exceptthe acknowledge mode transfer messages that are handled by the STM 334.

The CCP 338 provides an ISDN interface to the switch. The CCP 338performs switch interface processing including ISDN D-channel signalprocessing and multiplexing/demultiplexing of multiple D channels fromthe switch side T1 line 360. The CCP 338 accesses time slots on thebackplane E1 bus 346 containing ISDN channel signaling informationreceived from the switch via a communication module, such as an AT&TSPYDER chip. The CCP 338 also performs wireless personal communicationsystem layer 3 processing including call origination, call delivery,call disconnect and anchor ALT processing as well as the exchange ofmessages with the CAP 336 and the GRP 332 in support of layer 3processing.

The GRP 332 provides RPC 330 centralized functions such as networkmanagement, OMC interfacing, set up and management of TCP/IP connectionsto the access manager AM, wireless access communication system layer 3registration message processing, and load balancing between multipleCCPs 338 and CAPs 336.

As shown in FIG. 4, the STM 334 contains one central processor (CP) 362such as an INTEL 960 processor and 12 digital signal processors (DSP)s364 such as Texas Instruments TMS320C30DSP processors in the preferredembodiment. The STM 334 also has an E1 buffer 370 for communicating withthe switch 80, and a T1 communication processor 366, such as an AT&TSPYDER processor, for communicating with the RPs 50.

The E1 buffer 370 includes an input buffer having the same length,preferably 320 bytes, as an output buffer. The E1 buffer 370 contains aforward slot location pointer (FSLP) for determining the currentposition in the E1 buffer 370 for transmitting and receiving data. TheFSLP may be a register containing the offset into the buffer 370 of thecurrent byte being received or transmitted.

The T1 communication processor 366 is preferably configured so that aDS1 frame is divided into two superchannels. Each superchannel carries12 bytes of a wireless personal communication system payload group. Apayload group consists of 1680 bits (16 bursts, each burst having 105bits) of data from the RP 50. According to an aspect of the presentinvention, a circular buffer 367 having a buffer size that matches thesize of the RP time slot is provided. Preferably, the number of buffersmatches the size of the payload group. Such a configuration allowsefficient synchronization to the payload group in addition to efficientmanipulation of RP 50 time slot data. Preferably, the buffer 367consists of 16 circularly linked blocks having 12 bytes each. A suitablebuffer 367 may be configured within a communication interface such as aSPYDER interface module.

The DSPs 364 provide speech transcoding such as ADPCM to PCM or LDCELPto PCM, as well as wireless personal communication system layer 2message processing. The DSPs 364 also perform error checking and discarderroneous data received from the SU 20 in order to provide a more robustair interface. The DSPs 364 communicate with the CP 362 via an internalFIFO 378 mechanism. The CP 362 communicates with the CAP module 336 viathe backplane VME bus 348 and also communicates via the internal LAN 350during downloading and debugging.

A pair of DSPs 364 within each STM 334, one DSP 364 for processingreceive slots from the RP side and the other DSP 364 for processingreceive slots from the switch side T1 360. The CP 362 assigns each ofthe DSPs 364 into pairs where one DSP 364 is a Rx DSP 364 and the otheris a Tx DSP 364. Each DSP 364 pair converts ADPCM speech from the RPside T1 line 356 to PCM speech sent to the switch side T1 line 360, aswell as compresses PCM speech from the switch to ADPCM speech sent tothe RP 50.

The pair of DSPs 364 also perform wireless personal communication systemlayer 2 acknowledge mode transfer processing. This processing involvessplitting and recombining layer three messages into multiple layer twosegments; maintaining sequence number, checksum, and acknowledgmentdata; and retransmitting layer two messages. The layer three messagesare used for call setup, tear down, and automatic link transfer (ALT)requests. By using layer three message for ALT requests, the RPC 330provides a more robust call handoff. In addition, acknowledge modetransfer processing may be used to transport simple pack mode or circuitmode data. The pair of DSPs 364 also perform RP signal qualitymeasurements such as received signal strength indicator (RSSI)measurements. The pair of DSPs 364 processes the RSSI values receivedfrom the RP 50 and provides measurement information based on the RSSIvalues to the CP 362.

The DSP 364 periodically measures and averages a word error indicator(WEI) from the RP 50 to detect when the SU 20 has powered off ortraveled outside the range of the RP 50. In this case, the DSP 364informs the CCP 338 to disconnect any call in progress over that SU 20.

The CP 362 receives wireless personal communication system messages fromthe RP 50 and distributes data to the pair of DSPs 364. The CP 362 alsoreceives PCM speech from the switch and distributes the data to the pairof DSPs 364 handling the call. The CP 362 synchronizes wireless personalcommunication system messages on the RP side and performs wirelesspersonal communication system layer 2 and layer 3 message forwardingbetween the CAP 336 and the pair of DSPs 364. The CP 362 also marks thenext available slot for a call to the RP 50 using RSSI informationreceived from the DSPs 364 or using a round-robin scheme in some cases.Finally, the CP 362 processes anchor time slot interchange information.

As shown in FIG. 5, the CP 362 in the STM 334 preferably contains abackground process 400, an interrupt process 410, a DSP interface 422,and various memory components. The memory components include datastructures such as the VME buffer 416, the time slot control blocks 418,the uplink circular queue 424, the downlink circular queue 426, and theDSP flags 420. The VME buffer 416 is connected to the VME BUS 348 andallows communication between the STM 334 and the CAP 336. The time slotcontrol blocks 418 preferably include 16 blocks grouped into an arraywith one block for each RP T1 368 time slot. The time slot controlblocks 418 contain all the information required by a payload interruptprocess 412 to process voice and layer 2 messages related to each timeslot in the RP T1 line 368. The DSP flags 420 include an array of stateflags, one for each DSP 364. In the preferred embodiment there are 12DSPs so the array contains 12 DSP flag entries. Each flag entry is usedto mark whether a DSP 364 is available for use by the payload interruptprocess 412.

The interrupt process 410 performs all time critical processingincluding building a wireless personal communication system payloadenvelope and determining which time slot to mark as available. Thebackground process 400 performs non-time-critical functions required bythe STM 334.

In a preferred embodiment, the background process 400 consists of thebackground task 402, the signal quality task 404, and the configurationtask 406. The background task 402 preferably performs the followingfunctions: sending health check messages to the controlling CAP 336,checking the health of the DSPs 364 and reloading DSPs 364 reporting alarge number of errors, monitoring and, if necessary, resetting the E1hardware such as the E1 bus 346, processing commands received from theCAP 336, and monitoring STM 334 alarm conditions. STM 334 alarmconditions may include loss of T1 clock, loss of or unstable CAP 336interrupt, STM 334 to CAP 336 interface failure, DSP 364 failure, lossof synchronization at the RP T1 368, and E1 buffer 370 memory failure.

The signal quality task 404 periodically processes RP 50 signal qualitymeasurement data such as RSSI data received from the DSP 364 and usesthe signal quality data to mark the next best time slot available in thetime slot control block 418. Preferably, the configuration task 406 isresponsible for processing STM 334 configuration messages received fromthe CAP 336 during STM 334 initialization and reconfiguration. A moredetailed description of hardware initialization and configuration may befound in U.S. Pat. No. 5,299,198, the entire disclosure to beincorporated by reference herein.

The interrupt process 410 includes the wireless personal communicationsystem payload interrupt process 412 and an anchor interrupt process414. The payload interrupt process 412 is controlled by a controlinterrupt, preferably 500 micro seconds in duration, generated by theCAP 336.

In a preferred embodiment, the payload interrupt process 412periodically performs the following functions: voice processing, nextavailable slot marking, wireless personal communication system layer 2and 3 processing, and setting the time slot control block 418 activeupon receipt of a busy time slot indication. Voice processing involvesmoving data from the E1 input buffer 370 to the DSP 364 for compression,such as ADPCM compression, and then moving the compressed data to thetransmit buffer 367 for output to the RP T1 line 368. Voice processingalso includes receiving voice data from the receive buffer 367 anddecompressing the data to PCM data and placing the PCM data into the E1output buffer 370.

Layer 2 and 3 message processing involves processing both uplink anddownlink messages. For the uplink, a message received from the SU 20 viathe RP 50 is inserted into the uplink time slot circular queue 424. Forthe downlink, a message from the CAP 336 is inserted into the downlinktime slot circular queue 426 indicating the message is available fortransmission over the RP T1 line 368.

Preferably, the anchor interrupt process 414 is enabled when the STM 334is configured for anchor mode. The anchor interrupt routine 414preferably moves data from the E1 input buffer 370 for a particular DS0slot of the T1 line 372 to the E1 output buffer 370, effectively loopingdata from the switch.

The DSP interface module 422 may communicate with the DSPs 364 using theFIFO 374. The DSP interface 422 may send and receives formatted messagesto the DSPs 364 over a FIFO data bus 376 by reading and writing data.When a command is sent to the DSP 364 it may also be written into theFIFO 374. The CP 362 then issues an interrupt to the DSP 364, and theDSP 364 preferably processes the command and inserts a response backinto the bidirectional FIFO 374. Each response from the DSP 364 containsa response status code. In a preferred embodiment the following responsestatus codes are available: no error (0x00), PCM data returned (0x01),wireless personal communication system payload returned (0x02), layer 2message returned (0x03), layer 3 message returned (0x04), INFO₋₋ ACKbeing processed (0x05), layer 3 message segment in response (0x06),layer 3 message acknowledged (0x07), error (0xff). Each response fromthe DSP 364 also contains a NR/TR status field containing the status ofDSP 364 timer (TRxxx) and counter (NRxxx) parameters. The NR/TR statusfield is bit mapped with each bit set to 1 if the NRxxx counter valuehas been exceeded or the TRxxx timer has expired. In the preferredembodiment the NR/TR status field includes: bit 0--TR216 timer; bit1--TR217 timer; bit 2--TR218 timer; bit 3--NR210 count; bit 4--NR211count; bit 5--NR212 count; and bit 6--NR213 count.

Each CP 362 to DSP 364 command or response includes a time slot numbercorresponding to the RP T1 368 payload group being processed. In thepreferred WACS embodiment, the CP 362 allocates time slots 0 to 15 inthe payload groups A and B to the various DSPs 364 based on the numberof calls supported by the system. The CP 362 may either staticallyallocate the time slots or may dynamically allocate the time slots tobalance loading among multiple DSPs 364.

Some of the CP 362 to DSP 364 commands or responses includes an SC typefield and an SC data field that is dependent on the SC type field.Preferably, the SC type fields include the following types: systembroadcast (0x00)--the SC data field contains the available bandwidth;available channel (0x01)--the SC data field contains the availablebandwidth; busy channel with CCIC (0x02)--the SC data field contains theCCIC; busy channel with MC-S (0x03)--SC data field contains the 4 bitsegment of the MC-S; and busy channel with SDC (0x04)--SC data fieldcontains 4 bit directive of the SDC.

In a preferred embodiment, the following CP 362 commands and DSP 364responses may be supported: ADPCM compression, payload processing, layer2 message building, layer 3 message building, DSP configuration, linkdeactivation, and layer 3 polling. As shown in FIG. 6, the ADPCMcompress command has octet aligned fields containing 16 bytes of PCMvoice data. The ADPCM command also includes a length field containingthe number of following bytes in the command, an embedded operationschannel EOC field, SYC bits, a wireless personal communication systemsuperframe number, the time slot number, the SC channel type, and the SCchannel data. The ADPCM response contains a 12 byte payload envelopebuilt by the DSP 364 as well as the response status field, the lengthfield, and the NR/TR status field.

As shown in FIG. 7, the process payload command preferably contains thepayload envelope to be processed. The response contains a data fieldthat may be PCM data, a layer 2 message, a layer 3 message, or may beempty if a layer 3 message is pending. The response also includes theEOC, the signal quality RSSI value, the quality indicator (QI), the worderror index (WEI), the wireless superframe number, the time slot, andthe SC channel type and data.

As shown in FIG. 8, the build layer 2 message command preferablycontains a layer 2 message. The response includes the payload envelopecontaining the layer 2 message.

As shown in FIG. 9, the build layer 3 message command preferablyincludes a layer 3 message to be built into multiple payloads. Thecommand may include a payload containing a portion of the layer 3message. Subsequent commands sent to the DSP 364 result in a responseincluding payloads containing further segments of the layer 3 messageand a status of layer 3 message pending until the entire layer 3 messagehas been sent to the RP 50.

As shown in FIG. 10, the configure DSP command preferably loads theNRxxx and TRxxx parameters into the DSP 364.

The deactivate link command (not shown) causes the DSP 364 to stop anyprotocol processing and to reset its sequence numbers for the given timeslot.

As shown in FIG. 11, a layer 3 polling command may poll the DSP 364 fora layer 3 acknowledgement message originated by the SU 20. When the CP362 sends a layer 3 message to the DSP 364, the CP 362 preferably pollsthe DSP 364 until receiving a response having a response status of"layer 3 message received" indicating that the SU 20 has acknowledgedreceiving the layer 3 message. When the response indicates that the SU20 has acknowledged receiving the layer 3 message, the length field inthe response is zero and the response does not contain a payloadenvelope.

FIG. 12 shows how DSPs 364 may be allocated by the CP 362 for processingthe individual payload envelopes in a payload group. The letter "a" isthe first RF frequency in the payload group. As shown, the DSPs 364 aregrouped into pairs, one transmitting DSP and one receiving DSP. The DSPs364 are grouped into pairs so that signalling for ACK₋₋ MODE₋₋ TRANS andINFO₋₋ ACK message processing can occur using a dual port shared RAMbetween the pair of DSPs 364. Although FIG. 12 only shows allocation ofDSPs 364 for a single RF frequency, other allocations of DSPs 364 arepossible for handling multiple RF frequencies.

According to another aspect of the present invention, the STM 334operates in the following manner. For downlink voice processing, the STM334 moves voice data from the switch 80 to the SU 20 via the RP 50. STM334 downlink voice processing is initiated by the payload interruptprocess 382. After 16 bytes of data has been received into the E1 bufferarea 370, the CP 362 composes the 16 bytes of voice data into acompression command sent to a transmit (Tx) DSP 364. The Tx DSP 364converts the 16 bytes of PCM voice data into ADPCM data and forms apayload envelope containing the compressed data. The payload envelopcontaining the compressed speech data is then moved into the buffer area367 for transmission over the RP T1 line 368.

STM 334 uplink voice processing requires the STM 334 to move voice dataoriginated by the SU 20 to the switch. When a payload envelope has beenreceived in the buffer area 367 and a DSP 364 allocated to the time slotis available, the CP 362 payload interrupt process 382 formats thereceived data into a DSP process payload command and sends the commandto the Rx DSP 364. The DSP 364 then converts the ADPCM speech from thereceived payload into 16 bytes of PCM speech. The PCM speech is thenmoved from the FIFO 374 to the E1 buffer area 370 for transmission tothe switch.

STM 334 downlink message processing involves moving layer 2 messagesfrom the CAP 336 to the SU 20 via the RP 50. The CP 362 moves the layer2 message from the VME buffer 386 to the Tx DSP 364 using the buildlayer 2 message command. The Tx DSP 364 responds to the build layer 2message with a payload containing the layer 2 message. The payloadcontaining the layer 2 message is then moved to the buffer area 367 fortransmission over the T1 line 368.

STM 334 uplink message processing involves processing a message receivedfrom the SU 20. The payload envelope containing the message is passed toan available DSP 364. The DSP 364 responds to the CP 362 with the layer2 message that is then inserted into the uplink circular queue 424 inthe CP 362 where the message can be retrieved by the CAP 336 for furtherprocessing.

STM 334 anchor processing involves looping all received data from the E1input buffer 370 to the E1 output buffer 370 for a designated time slot.Anchor processing is done by the CP 362 using the anchor interruptprocess 384.

As shown in FIG. 13, the CAP 336 preferably includes various processingand data elements. In a particularly preferred embodiment, the CAP 336includes a wireless personal communication system layer 2 unit 500 whichincludes a system broadcast task 502, a wireless personal communicationsystem link manager 506, a wireless personal communication system layer2 state machine 504, and a radio link control block 508.

The system broadcast task 502 may have three message cues. An alertchannel cue system, system information channel cue and priority requestchannel cue. The system broadcast task 502 preferably formulates asystem broadcast channel (SBC) Superframe 510 from the three messagecues which is sent to the STM 334. Within the STM, the SBC Superframemay be received in a VME SBC area 516 of the VME buffer 416. The systembroadcast task 502 is preferably awakened every 1.02 seconds since theSBC Superframe 510 has a period of 1.024 seconds. The system broadcasttask 502 may also communicate with the state machine 504.

The link manager 506 communicates with a router task 516 via messagesfrom the CCP 338 over the internal LAN 350 and sends and receives layer2 and 3 messages to the STM 334. The link manager 506 also sends linkcommands to an STM manager task 514 in communication with the STM 334.The VME buffer 416 has a layer 2 and layer 3 area 518 and aconfiguration area 520 for receiving and sending messages to the linkmanager 506 and the STM manager task 514. The link manager 506 alsocommunicates with the state machine 504. The link manager 506 isresponsible for establishing and maintaining radio links. The linkmanager 506 receives and processes CCP layer 3 messages and forwards anyalert commands received from the CCP to the system broadcast task 502.

Messages sent to the STM 334 from the link manager 506 include headerinformation such as the STM slot number, payload group number, time slotnumber (0/15), and message type (layer 2 or layer 3). The STM slotnumber, payload group number and time slot number constitute a radiolink identifier RLID used to identify messages for active links. Theradio link control block RLCB 508 contains an entry for each radio link.Each link is identified by the associated STM slot number, payload groupnumber and time slot number. The RLCB 508 contains the following fields:RLID, assigned STM chassis number, assigned time slot number and currentstate.

The STM manager task 514 monitors and controls every STM 334 associatedwith the CAP 336. The STM manager 514 performs the functions ofinitializing the STM monitoring the STM 334 for alarms and failures,verifying software in each STM 334, reconstructing data structures fromthe STM 334 in the event of a failure, and providing utilities andwriting commands over the VME bus 348.

The state machine 504 in the preferred embodiment has been implementedas a layer 2 state table that is shown in Table A below. Processingwithin the state machine 504 is preferably performed as directed by thestate table. The state table includes various procedures described indetail below.

                  TABLE A                                                         ______________________________________                                        WACS/PACS Layer 2 State Table                                                 States                                                                                       Initial                                                                Null   Access        Link  ALT In                                     Events  State  Pending Link Up                                                                             Suspend                                                                             Progress                                                                             Anchored                            ______________________________________                                        Initial SOO                                                                   Access Req.                                                                   Initial        SO1                                                            Access Cnf                                                                    Initial        SO2                                                            Access Deny                                                                   L3 Message             SO1                                                    Link                   SO3                                                    Suspend                                                                       Link Resume                  SO8                                              Access                 SO9   SO9                                              Release                                                                       ALT     SO4                        SO4    SO4                                 Request                                                                       ALT                                SO5                                        Complete                                                                      ALT Deny                           SO1                                        ALT Exec                           S10                                        ALT Ack                            S10                                        Set Anchor                         SO6                                        Release                                   SO7                                 Anchor                                                                        Set Link                     SO1                                              Release                      SO1                                              Link                                                                          ______________________________________                                    

WACS STATE PROCEDURES State Procedure S00

This state procedure performs the following when an Initial AccessRequest is received in Null State.

1. Set the current state to Initial Access Pending.

State Procedure S01

1. Set the current state to Link Up.

State Procedure S02

This state procedure performs the following.

1. If anchor channel is allocated then activate voice channel on theanchor channel.

2. Deallocates all link resources.

3. Set the current state to the Null State.

State Procedure S03

This state procedure performs the following when a Link Suspend isreceived in the Link Up State.

1. Set the current state to Link Suspend State.

2. Forward LINK₋₋ SUSPEND to CCP.

3. Send Mute command to STM.

State Procedure S04

This state procedure performs the following when an ALT Request isreceived in Null State.

1. Set the state to the ALT In Progress.

2. Forward ALT₋₋ REQ to CCP.

State Procedure S05

This state procedure performs the following.

1. If (Intra-ALT) then switch the voice path to the new time slot orSTM.

2. Stop TN202.

3. Set the current state to Link Up.

4. Forward ALT₋₋ COMP to CCP.

State Procedure S06

This state procedure performs the following.

1. Set the current state to Anchored.

2. Send command to Anchor STM to anchor a channel.

State Procedure S07

This state procedure performs the following.

1. Release all call resources.

2. Set current state to Null State.

State Procedure S08

This state procedure performs the following.

1. Set the current state to Link Up.

2. Forward LINK₋₋ RESUME to CCP.

State Procedure S09

This state procedure performs the following.

1. Set the current state to Null State.

2. Forward ACCESS₋₋ RELEASE to CCP.

State Procedure S10

This state procedure sets the current state to ALT In Progress.

As shown in FIG. 14, the CCP 338 includes process components that may beexecuted on a processor such as an INTEL 960 processor. The CCP 338 isloaded with multitasking operating system software such as VXWORKS fromWind River Systems. The process components include a management task 550that initiates and directs messages between the other components, a callcontrol task 552 that implements a layer 3 wireless personalcommunication system state machine, and an ISDN processing task 554. TheISDN processing task 554 implements layers 1, 2, and 3 of the ISDNaccess signaling protocol defined as CCITT standard Q931/Q921 andcontrols a synchronous protocol data formatter device that communicateswith the switch 80 at the central office. The ISDN task 554 is performedby commercially available ISDN software such as the ISDN softwareavailable from DGM&S Inc. at 1025 Briggs Road, Suite 100, Mt. Laurel,N.J. 08054.

The management task 550 preferably spawns the other components androutes all incoming and outgoing messages from the AM 90 and the CAP336. In a preferred embodiment, the call control task 552 has one threadfor each active call. Each thread may be an instantiation of thewireless personal communication system layer 3 state machine defined intable form in Appendix A. The state machine table defined in Appendix Acontains many terms defined in the Bellcore specification. Also, personsskilled in the art will recognize that the Intelligent ServicesPeripheral (ISP) supports the AM 90.

The call control task 552 may also have a thread that performs ALT DNmanagement and a thread that routes messages to and from each of thestate machine threads. The Global Resource Processor (GRP) 332 is acollection of tasks and functions that are executable preferably on aCPM board including an Intel 960 processor. As shown in FIG. 15, the GRP332 includes a message router 600, a resource manager (RM) 604, a calldistribution manager (CDM) 606, an administrative interface 608, anetwork management system (NMS) agent 610, and an Input/Output portmanager (IOPM) 612. The message router 600 communicates with the AM 90and the OMC 90 over the backbone LAN 352 and communicates with the otherRPC components over the RPC LAN 350. The message router 600 is connectedwith the RM 604, the NMS agent 610, and the CDM 606. The CDM 606 isconnected to the RM 604 through a congestion data block 616. The CDM 606is also connected to the administrative interface 608 and the messagerouter 600.

The IOPM 612 is connected to an IO card function module 614 thatcommunicates with external communication links such as T1 lines. TheIOPM 612 is connected to the CDM 606 and the administrative interface608.

The RM task 604 is the central RPC 330 component responsible forhandling resource shortages throughout the RPC 330. This task 604manages buffers and queue shortages on RPC 330 components indicating acomponent's CPU is over-utilized with respect to the component'savailable memory. The RM 604 keeps track of global resources enablingthe CDM 606 to balance the load among RPC processors. The RM 604 maythrottle system activity within its control such that the offeredtraffic load is balanced against the available system resources. The RM604 prevents the system from reaching a critical point in whichincreased activity results in a collapse of the components under theRM's 604 control.

The RM 604 manages congestion report messages received from componentsin the RPC 330 of the associated GRP 332. For each congestion reportmessage, the RM 604 records appropriate statistics, and sends anacknowledgement to the sending component. The RM 604 manages a systemresource table based on the congestion report messages. The RM 604 mayreceive commands for statistics reports from the NMS Agent (AGNT) 610.

The RM 604 recognizes the onset of system wide congestion in a way thatprotects against further congestion, reacts to congestion in a mannerthat is specific to the area of congestion and corresponds to theseverity of the congestion level. The RM 604 allocates and tracks systemresources available within the RPC so that traffic is prioritized in theorder of emergency calls, existing traffic, and then new traffic withrespect to the available resources.

The GRP 332 provides an interface to the OMC 70 for performing networkmanagement functions. The Network Management Agent 610 provides atransport mechanism to support these functions or may perform networkmanagement functions directly. The NMS Agent 610 performs the followingfunctions: maintains statistics by application tasks in a global memoryarea, provides statistics to the OMC 70, monitors trace and controlflags, maintains summary status information, processes alarms and callcontrol requests, and supports processor downline loading andreconciliation.

Call control requests include call monitoring, call tracing, call pathallocation, forced call handoff, and forced call clearing. The NMS agent610 also handles call record management, component control in responseto OMC commands, and debugging and testability support such as uplinedump, and memory read/write.

The Call Distribution Manager (CDM) 606 provides call distribution andnetwork management services. When a call setup is initiated, the CDM 606determines the call identifier (RCID) and selects a CCP 338 for thecall. The CDM 606 handles call manipulation requests (by controlling theappropriate CCP 338) from the OMC 70 such as call monitoring, forcing anALT, clearing a call and fetching the status or statistics of a call.

The message router 600 allows the GRP 332 to perform call processingfunctions including distributing requests for call originations amongactive CCPs 338, providing via the Backbone LAN 352 an interface toother RPCs, initiating graceful disconnection of active calls when CCPs338 fail, and polling active CCPs 338 for current call statusinformation when switching in a backup GRP 332.

The IOPM 612 indicates when T1 line failures occur by frequently pollingthe IO Cards 614 minimizing the time between failure and resultingaction. The IOPM 612 maintains and reports to the OMC 70 the status ofI/O ports. The IOPM 612 also monitors T1 I/O Ports for alarm conditionsand reports events to the OMC 70. Finally, the IOPM 612 may performswitchover for backup T1 cards in response to alarm conditions or to anoperator request.

Another preferred embodiment allows the RPC 330 to perform functionstraditionally handled in the AM 90. An RPC 330 performing traditionallyAM functions may be implemented by adding a GRP 332 with an associateddisk drive to the RPC 330. The disk drive includes various databases.These databases may provide for subscriber features, dynamic subscriberdata, radio equipment configuration, altering area mapping, terminallocation, routing instructions, call processing activity information,subscriber status, encryption information, or other subscriber desiredinformation.

Traditionally AM functions provided in the RPC 330 on the added GRP 332include authenticating and registering subscribers, administrating theradio network, managing billing information, and interacting with thedatabase to determine the subscriber's radio location, status, alertinginformation, and terminating features. The GRP 332 may also control thetwo-stage alerting process by first locating the SU 20 and thendirecting the switch to establish a voice connection to the RP 50 andalert the subscriber. The GRP 332 works with the switch to provideoriginating service for wireless calls. The GRP 332 instructs the switch80 to associate the call origination with the subscriber. The GRP 332may query the database for the subscriber's originating features andcontrol the switch to provide that set of features.

Although a single added GRP 332 and disk drive have been disclosed, thepreferred embodiment is not limited to the number or arrangement of GRPs332 or storage devices such as disk drives used for performing at leastsome traditionally AM functions. A network including multiple GRPs 332,storage devices, or other RPC 330 processing components may be arrangedin various ways for efficiently implementing traditionally AM functionsin the RPC 330 of the preferred embodiment.

FIG. 16 shows messages that may be transmitted between various RPC 330elements and the SU 20 via the RP 50 for a layer 2 initial accessmessage. The CP 362 (labeled STM960 in FIG. 16) receives a payload fromthe RP T1 line 368 communicating with the SU 20. The CP 362 distributesthe payload to multiple Rx DSPs 364 to handle the individual time slotsin the payload. Each Rx DSP 364 parses the time slot fast channel anddetermines that the payload is carrying an initial access message. TheDSP 364 resets the acknowledge-mode-transfer link variables (NS/NR) andthen forwards the initial access message through the CP 362 to the CAP336 via the internal VME bus 348. The link manager 506 in the CAP 336performs the necessary layer 2 protocol processing using the statemachine 504 and sends an access confirm message via the CP 362 to the TxDSP 364. The Tx DSP 364 formats the access confirm message in the fastchannel of the time slot into a payload to be sent to the SU 20 over theRP T1 line 368.

FIG. 17 shows an example of the message flow for a call originating froman SU 20. The Rx DSP 364 parses the fast channel and determines the callorigination message is an acknowledge-mode-transfer (layer 3) message.The Rx DSP 364 performs acknowledge-mode-transfer processing includingassembling the call origination message from the multiple segmentsreceived in the fast channel. The Rx DSP 364 also validates the checksumand sends an Info Ack Layer 2 message via shared RAM to the Tx DSP 364for transmission over the RP T1 line 368 to the SU 20. When the completelayer 3 call origination message has been received, the Rx DSP 364forwards the message to the CCP 338 via the CAP 336.

The CCP 338 performs layer 3 processing upon receiving the callorigination message as defined in the layer 3 state machine (seeAppendix A) and executed by the call control task 552. Layer 3processing includes message exchange with the AM 90 and sending an RCIDassign layer 3 message to the Tx DSP 364 via the CAP 336 and CP 362. TheTx DSP 364 fragments the layer 3 message into multiple segments ifnecessary and sends the RCID assign message to the SU 20. The Tx DSP 364then performs ack-mode transfer processing such as waiting for any layer2 info ack messages and retransmitting any unreceived message segments.The other messages shown in FIG. 17 are processed in a similar manneruntil the call is set up and a communication path is established throughthe RPC 330.

FIG. 18 shows an example of the RPC 330 message flow for a calldelivery. First the CCP 338 receives an alert message from the AM 90 andsends an internal alert message to the CAP 336. The CAP 336 uses thesystem broadcast task 502 to format an SBC superframe 510 that is sentto each STM 334 managed by that CAP 336. The SBC superframe message isthen transmitted by each STM 334 in the SBC slot of the payload on theRP T1 line 368. The remaining messages are layer 2 and layer 3 messagesthat proceed in a similar manner as described for call origination untila call connection is established.

FIG. 19 shows an example of the RPC 330 message flow for an automaticlink transfer. First, the DSP 364 receives a first and second portion ofa layer three automatic link transfer (ALT) request message. The RPC 330forwards the ALT₋₋ REQ message to the CAP 336. The CAP 336 sends anALT₋₋ EXEC message to the DSP 364 which in turn sends the ALT₋₋ EXECmessage to the SU 20. The SU 20 sends an ALT₋₋ COMP message to the DSP364. The DSP 364 passes the ALT₋₋ COMP message on to the CAP 336. TheCAP 336 sends a Release Link message to the old STM 334 and then sends aconnect link message to the new STM 334 to complete the call handoff. Bysending a layer three ALT request message, the RPC 330 provides morerobust call handoff processing.

Additional advantages and modifications will readily occur to thoseskilled in the art. The invention, in its broader aspects, is thereforenot limited to the specific details, representative apparatus, andillustrative examples shown and described. Various modifications andvariation can be made to the present invention without varying from thescope or spirit of the invention, and it is intended that the presentinvention cover the modifications and variations provided they comewithin the scope of the appended claims and their equivalents.

    __________________________________________________________________________    Appendix A                                                                    Table of Layer 3 States in a Wireless Personal Communications                 __________________________________________________________________________    System                                                                         ##STR1##                                                                      ##STR2##                                                                      ##STR3##                                                                      ##STR4##                                                                      ##STR5##                                                                     __________________________________________________________________________    4.2 RPC ACTIONS                                                               1. Send TERM.sub.-- REG.sub.-- REQ to ISP. Start TC3031                       2. Stop TC3031. Start TC3191. Send WACS.sub.-- TERM.sub.-- REG.sub.-- ACK     to the SU                                                                     3. Stop TC3191. Release call resources.                                       4. Send CALL.sub.-- REQUEST to ISP                                            5. Send RCID.sub.-- ASSIGN to SU. Send ISDN.sub.-- SETUP to CO. Start         T-ANS. Record Time Stamp #1                                                   6. Send WACS.sub.-- CALL.sub.-- PROC to SU.                                   7. Sends no messages.                                                         8. Stop T-ANS. Record Time Stamp #2. Send WACS.sub.-- COnnect to SU.          9. Send ISDN.sub.-- CONNECT.sub.-- ACK to CO. Send P.sub.-- CONNECT to        ISP.                                                                          10. Send WACS.sub.-- ALERT to SU NR201 times. Store RCID.sub.-- ID and        Int.sub.-- DN.                                                                11. Send ALERT.sub.-- ACK to ISP. Start TC3011.                               12. Stop TC3011. Start TC3021. Send RCID.sub.-- ASSIGN to SU.                 13. Stop TC3021. Record Time Stap #1. Send WACS.sub.-- INCOMING.sub.--        CALL to SU.                                                                   14. Send ISDN.sub.-- Alerting.                                                15. Send ISDN.sub.-- CONNECT to C.O. Record Time Stamp #2.                    16. Send P.sub.-- CONNECT to ISP.                                             17. Send P.sub.-- DISCONNECT to ISP. Start TC3192.                            18. Stop TC3192. Send ISDN.sub.-- DISC to the CO. Record Time Stamp #3.       Send WACS.sub.-- RELEASE to SU.                                               19. Stop TC3192. Send ISDN.sub.-- RELEASE to the CO. Send WACS.sub.--         DISCONNECT to SU. Start TC3111.                                               20. Send ISDN.sub.-- REL.sub.-- COMP to C.O.                                  21. Send WACS.sub.-- RELEASE to SU.                                           22-24. No Action listed.                                                      25. Send P.sub.-- DISCONNECT to ISP. Start TC3182. Record Time Stamp #3.      26. Send FURTHER.sub.-- CALL.sub.-- INFO an P.sub.-- REL.sub.-- COM to        ISP.                                                                          27, 28. No Action listed.                                                     29. Stop TC3192. Send ISDN.sub.-- DISC to the CO. Record Time Stamp #3.       30. No Action listed.                                                         31. Send ISDN.sub.-- REL.sub.-- COMP to CO. Send P.sub.-- REL.sub.-- COM      to ISP.                                                                       32. Send WACS.sub.-- RELEASE to SU. Stop TC3031. Start TC3191.                33. Stop TC3191.                                                              34. Send WACS.sub.-- RELEASE TO SU. Start TC3191.                             35-49. No Action listed.                                                      50. Send ALT.sub.-- EXEC to SU. Start TN202.                                  51. Send ALT.sub.-- COMP to ISP Release old radio link.                       52. Send ALT.sub.-- ACK to SU. Send ISDN.sub.-- SETUP for anchor RPC's        ALT.sub.-- DN TO CO. Start T-ANS.                                             53, 54. No Action listed.                                                     55. Bridge the original call to the loop-back call. Send ISDN.sub.--          CONNECT TO SU.                                                                56. Stop T-ANS. Send ALT.sub.-- EXEC to SU. Send ISDN.sub.-- CON.sub.--       ACK to CO. Start TN202.                                                       57. Send ALT.sub.-- EXEC to SU.                                               58. No Action listed.                                                         59. Send ALT.sub.-- COMP to ISP.                                              60. Send ALT.sub.-- EXEC to SU. Disconnect "bridge".                          61. Send ALT.sub.-- COMP to ISP.                                              62. Send ALT.sub.-- COMP to ISP. Send ISDN.sub.-- DISC to CO for loopback     call.                                                                         63. Send ISDN.sub.-- REL.sub.-- COMP to CO for loopback call.                 64. Send ISDN.sub.-- REL to CO for loopback call.                             65. Send ISDN.sub.-- DISC to CO. Time Stamp #3.                           

What is claimed is:
 1. A radio port controller in a wireless personalcommunications system comprising:a first interface module incommunication with a radio port; a second interface module incommunication with a digital switch wherein said second interface modulecomprises a plurality of interface cards, each card having a first setof pins for producing a T1 signal and a second set of pins for producingan E1 signal; at least one switching transcoder module (STM) incommunication with said first and second interface modules; and acommunication backplane comprising:a T1 databus in communication withsaid STM and said first interface module; an E1 databus in communicationwith said STM and said second interface module; a plurality of slotsadapted to receive said interface card; and a control switch forselectively connecting one of said sets of pins to said E1 databus. 2.The radio port controller of claim 1 wherein said STM comprises:a firstcommunications buffer coupled to said first interface module forcommunicating with said radio port; a second communications buffercoupled to said second interface module for communicating with saiddigital switch; a plurality of digital signal processors (DSPs) incommunication with said first communications buffer and said secondcommunications buffer, at least one of said DSPs having an interruptless than 1 millisecond; and a central processor in communication withsaid DSPs for controlling transmission of data between said DSPs andsaid communications buffers.
 3. The radio port controller of claim 1wherein said first interface module includes at least one T1 card. 4.The radio port controller of claim 3 wherein each T1 card is coupled toat least one T1 line, and each STM processes messages from at least oneof said T1 cards.
 5. The radio port controller of claim 1 wherein saidSTM includes a first DSP for processing incoming messages and a secondDSP in communication with said first DSP for processing outgoingmessages.
 6. The radio port controller of claim 1 wherein said STMcomprises:a plurality of DSPs capable of processing both digitized voiceand personal communication system messages; and a plurality of memorybuffers in communication with said DSPs, wherein said buffers arecircular buffers adapted to receive and transmit data messages betweensaid first and second interface modules.
 7. The radio port controller ofclaim 6, wherein at least one of said personal communication systemmessages comprises a layer three automatic link transfer requestmessage.
 8. The radio port controller of claim 6 wherein each STMfurther includes a central processor for allocating each time slot ineach T1 line to at least one of the DSPs.
 9. The radio port controllerof claim 8 wherein the central processor communicates with each DSPusing inter-processor data messages.
 10. The radio port controller ofclaim 1 further including at least one call control processor (CCP) incommunication with said STM.
 11. The radio port controller of claim 10wherein said CCP includes an ISDN state machine for processing ISDNmessages and a WACS layer 3 protocol state machine for processing WAGSlayer 3 messages.
 12. The radio port controller of claim 10 wherein saidCCP includes a multi-tasking operating system adapted to create a threadsupporting a call processing routine for each active call.
 13. The radioport controller of claim 10 further including at least one channelaccess processor (CAP) in communication with each of said STMs and eachof said CCPs, said CAP for processing layer 2 personal communicationsystem messages.
 14. The radio port controller of claim 13 wherein saidCAP includes a communication interface and a common processor module.15. The radio port controller of claim 13 further including a globalresource processor in communication with at least one of said CCPs andat least one of said CAPs for balancing loading among said CCPs and saidCAPs.
 16. A radio port controller in a wireless personal communicationssystem comprising:a first interface module in communication with a radioport; a second interface module in communication with a digital switch;and a communication backplane in communication with said first andsecond interfaces, said backplane including a T1 databus, an E1 databus,a plurality of slots switchably connected to said T1 and E1 databuses,and a control switch for selectively connecting each of said slots toone of said databuses.
 17. A radio port controller in a wirelesspersonal communications system comprising:a first interface module incommunication with a radio port; a second interface module incommunication with a digital switch; at least one switching transcodermodule (STM) in communication with said first and second interfacemodules; at least one call control processor (CCP) in communication withsaid STM; and at least one channel access processor (CAP) incommunication with each of said STMs and each of said CCPs, said CAP forprocessing layer 2 personal communication system messages.
 18. The radioport controller of claim 17 wherein said CAP includes a communicationinterface and a common processor module.
 19. The radio port controllerof claim 17 further including a global resource processor incommunication with at least one of said CCPs and at least one of saidCAPs for balancing loading among said CCPs and said CAPs.